Convertible contact structure for an electromagnetically operated switch



7 April'7, 197 E E. J. NIELSE ETAL E 3,505,625

CO V RTIBLE C I led Sept ON T S CTURE FOR AN E TR GNETIC Y OPERATED SWITCH INVENTOR. ERIK J. NIELSEN ALLIN W. SCHUBRING United States Patent CONVERTIBLE CONTACT STRUCTURE FOR AN ELECTROMAGNETICALLY OPERATED SWITCH Erik J. Nielsen, Mequon, and Allin W. Schubring, Milwaukee, Wis., assignors to Square D Company, Park Ridge, Ill., a corporation of Michigan Filed Sept. 12, 1968, Ser. No. 759,350 Int. Cl. H01h 45/00 US. Cl. 335132 9 Claims ABSTRACT OF THE DISCLOSURE An arrangement for achieving conversion of the contacts of a relay from a normally open to a normally closed contact operation and vice versa. The conversion is accomplished by connecting a rear set of movable contacts of the relay to a common terminal and providing a removable member which may be selectively secured to either of two stationary contact supports at the front of the relay.

This invention relates to electric circuit controlling devices and more particularly to electromagnetic control devices which have contacts which may be readily converted to accommodate the requirements of a control systern.

When relays are wired to control the sequence of operation of machine tools, conveyer installations, and the like, two conflicting interests arise. The manufacturer of the machine tool finds it is to his best interests to use the maximum number of contacts of each relay in the control for the machine tool to thus decrease the cost of installation. On the other hand, as the user of the machine tool frequently is required to change the operation of the machine tool, rewiring of the circuits of the control may be necessary. Thus it is desirable from the users standpoint that the relays have unused switching contacts which may be utilized to effect the desired change in the sequence of operation of the machine tool.

To satisfy the above requirements, relays are furnished with convertible contacts which may be changed to provide normally open or normally closed switching operations. To provide this result, the movable contacts of the relay usually are arranged so their positions can be changed. This requires that the relay be disassembled and re-assembled to accomplish the conversion of the contacts.

It is an object of the present invention to provide an electric switch with a structure which will permit the operation of the switch to be readily converted from a normally open to a normally closed contact operation and vice versa.

An additional object is to provide an electric switch with a structure wherein conversion of the switch from a normally closed to a normally open contact type of operation of the switch, and vice versa, may be accomplished by removing a terminal member from its connected position on a support for one of the stationary contacts of the switch and reconnecting the terminal member on another support for a stationary contact of the switch.

A further object is to provide an electric switch with a structure wherein conversion of the switch from a normally closed to a normally open contact type of operation of the switch, and vice versa, may be accomplished by removing a terminal member from its connected position on a support for one of the stationary contacts of the switch and reconnecting. the terminal member on a support for another stationary contact of the switch, and wherein the terminal member when connected to the support for one of the stationary contacts prevents access to support for the other. stationary contact.

Another object is to provide an electric switch, such as ice an electromagnetically operated relay, with a first station ary pair of contacts which are spaced between a center line and a rear wall of a support for the stationary contacts and a second pair of stationary contacts which are spaced between the center line and a front wall of the support and a movable contact structure which is movable along the center line between two spaced positions to bridge one of the contacts of the first and the second pairs of stationary contacts when in one position and to bridge another one of the contacts of the first and the second pairs of stationary contacts when -in a second of the two positions, and to electrically interconnect the first pair of contacts with a common wire terminal that is accessible from the exterior of the support and to provide only one of the second pair of stationary contacts with a separable wire connecting terminal memberwhich may be readily removed and connected to the other of said second pair of stationary contacts to change the operation of the relay from a normally open to a normally closed contact operation and vice versa, and to arrange the separable wire connecting terminal member so it is accessible from the exterior of the support when it is attached to one of said second pair of stationary contacts and prevents access to the other of said second pair of stationary contacts.

Further objects and features of the invention will be readily apparent to those skilled in the art from the specification and appended drawing illustrating certain preferred embodiments in which:

FIG. 1 is a front view in elevation of an electromagnetc switch including a convertible contact structure according to the present invention.

FIG. 2 is a side view of the switch in FIG. 1 with a portion thereof shown in cross section as taken generally along line 2 in FIG. 1. I

FIG. 3 is a side view in cross section of a modified form of the contact structure of the switch detached from a base for the switch as taken generally along line 5 in FIG. 1 and showing the contacts of the switch in an electric circuit.

FIG. 4 is a perspective view of a wire connecting member as used in the switch in FIG. 1.

The electric circuit controlling device or switch 10, shown in the drawing, includes a base 12, preferably formed as a unitary part of die cast metal material to have a set of openings 14 for mounting the switch 10 on a vertical panel, not shown, with an electromagnet assembly 16 positioned at the lower vertical portion of the base 12. The opening 14 at the top of the base is in an inverted key-hole shaped opening and the pair of openings 14 at the bottom of the base 12 are slots having exposed ends at the bottom edge of the base 12. The structure of the base 12, the electromagnet 16, the arrangement for mounting the electromagnet 16 on the base 12 and structure for causing linear reciprocable movement of a movable contact carrier 18 is fully disclosed and described in an application for United States Patent, Ser. No. 759,351, which is concurrently filed herewith and has been assigned by the inventor Kenneth J. Marien to the assignee of the present invention.

The switch 10 includes an insulating support 20- which is preferably formed of a suitable molded material to have a pair of spaced side walls 21 and oneor more spaced parallel partitions 22 extending forwardly of a rear wall 24 and downwardly of a top wall 26 to divide the space between the side walls 21 into a plurality of chambers 28 which are identical and spaced from each other in the insulating support 20. While in the drawings only a single partition 22 provides the support 20 with a pair of identical chambers 28, it is apparent additional partitions will provide the support with a greater number of chambers as required. The partition 22- extends forwardly of the rear wall 24 and downwardly of the top Wall 26 so each of the chambers 28 has an open front end 30 and an open bottom end 32, as defined by the front and bottom edges of the partition 22 and the walls 21. Extending between the partition 22 at the open front end 30 of each chamber 28 is a pair of mounting portions 34 and 36 and a support ledge 38 which connect the partition 22 with the side walls 21.

The base 12 is provided with an upwardly facing wall 40 from which a boss 42 projects in spaced relation to a rear wall 44 of the base 12. The support 20 is positioned on the base 12 by a portion of the rear wall 24 which is received in the space between the boss 42 and the rear wall 44 and a screw 46 which extends through an opening in the support 20 into a threaded opening in the base 12. Movable in the support 20 along an axis indicated by a numeral 48 is the movable contact actuator 18.

The partition 22- is provided with an upwardly extending slot 52 extending along the axis 48 to the top wall 26-. The movable contact carrier 18, which is preferably formed of a suitable molded insulating material, has a base portion 54 extending along a space between the bottom edge of the partition 22 and a portion 55 guided in the slots 52. Additionally, the movable contact carrier 18 has portions which present an individual movable contact carrying portion 56 in each of the chambers 28. Each of the movable contact portions 56 is provided with an opening 58 having an upper wall 60 and a lower wall 62. Positioned in each opening 58 is a movable contact assembly which, in the embodiment shown, includes a pair of movable contact fingers 63 and 64 and a spring 65. The spring 65* is positioned between the contact fingers 63 and 64 to urge a medial portion of the contact finger 63 into engagement with the upper wall 60 and a medial portion of the contact finger 64 into engagement with the lower wall 62. The contact fingers 63 and 64 each have contact surfaces thereon extending on opposite sides of the axis 48 in the chamber 28. The contact surfaces 63a and 6311 on the contact finger 63 face upwardly in the chamber 28 while the contact surfaces 64a and 64b on the contact finger 64 face downwardly in the chamber 28. As shown, the contact surfaces 63a and 64a are located at one side of the contact carrier 18 in the chamber 28 between the axis 48 and the rear wall 24 and the contact surfaces 63b and 64b are located on a side of the contact carrier 18 between the axis 48 and the open front end 30 with the fingers 63 and 64 extending in spaced parallel planes that are normal to the axis 48. A spring 66 positioned between the movable contact carrier 18 and portions of the partition 22 surrounding the slot 52 constantly urges the movable contact carrier 18 downwardly in the support 20 and, if desired, the upper portion of the contact carrier 18 may be provided with a projection 50, which extends through an opening in the top wall 26 so the switch may be manually operated.

The switch 10 includes a pair of contact surfaces 68 and 70 which face each other and are positioned in each of the chambers 28 in spaced relation to a side of the actuator 18 between the axis 4 8 and the rear wall 24. The contact surfaces 68 and 70 are located to be respectively engaged by the contact surfaces 63a and 64a. The switch 10 also includes a pair of contact surfaces 72 and 74 which face each other and are positioned in each of the chambers 28 in spaced relation to a side of the contact carrier 18 between the axis '48 and the open end 30 to be respectively engaged by the contact surfaces 63b and 64b.

The contact surfaces 68 and 70 are positioned within the chamber 28 by a member 76 which electrically interconnects the contact surfaces 68 and 70'. The member 76 at one end has a portion 78 providing a common support for the contact surfaces 68 and 70 and has a portion 80 extending external of a forward portion of the top wall 26 which provides a support for a wire connecting terminal member including a screw 82 and wire clamp 84 for the purpose of connecting the contact surfaces 68 and 70 to one s de of a source S of e ectric en rgy as shown in FIG. 3. The member 76 is maintained in the chamber 28 by a screw 86 which extends through an opening in the top wall 26 and is threaded into a threaded opening in a portion of the member 76 located between the portions 78 and 80.

The contact surface 72 is secured on an end portion of a member 87 which is secured by a screw 88 on the mounting portion 34 to have a terminal connecting portion 90 extending to be externally accessible of the open front end 30 of the chamber 28. The terminal connecting portion 90 is provided with a notch 92 that faces upwardly. Similarly, the contact surface 74 is secured on an end portion of a member 94 which is secured by a screw 96 on the mounting portion 36. The member 94 has a portion '98 resting on the support ledge 38 and extends to a terminal connecting portion 100 which extends to be externally accessible at the open front end of the chamber 28 at a location spaced below the terminal connecting portion 90. The terminal connecting portion 100 also has an upwardly facing notch 102 therein.

Securable to either of the terminal connecting portions 90 or 100 that are accessible at the open front end of each of the chambers 28 is a terminal connecting member 104 which is most clearly shown in FIG. 4. Each of the members 104 has a wire connecting terminal portion 106 at one end that includes a screw 108 and a wire clamp 110 whch will secure a bared end of an electrical conductor and a mounting portion 112 at its other end which is arranged to be secured by the notches 92 or 102 to either of the terminal connecting portions 90 or 100. Displaced at one side of the portions 106 and 112 is a portion 114 which interconnects the terminal portion 106 with the mounting portion 112. The interconnecting portion 114 extends in a plane that is perpendicular to planes in which the terminal portion 106 and the mounting portions 112 are disposed and is arranged to position the terminal portion 106 forwardly of the mounting portion 112 when the terminal connecting member 104 is mounted in either of its two positions on the switch 10. In this connection it should be noted, as shown in FIG. 1, that the terminal connecting portion 90 is displaced to the left of a centerline through each of the chambers 28 which are respectively designated as A and B, while the terminal connecting portion 100 is displaced to the right of the respective centerline. Thus the terminal connecting portion 90 in the chamber A will be spaced from the partition 22 and the terminal connecting portion 90 in the chamber B will be spaced from the right side wall 21 of the switch 10. Similarly, the terminal connecting portion 100 in the chamber A will be spaced from the left side wall 21 of the switch 10 and the terminal connecting portion 100 in the chamber B will be spaced from the partition 22. The spaces between the terminal connecting portions 90 and 100 and their adjacent partition 22 or side walls 21 are used to receive the interconnecting portion 114 of the terminal connecting member 104.

The mounting portion 112 has a threaded opening which receives a mounting screw 118 having a head portion disposed on a forward side of the mounting portion 112. Extending rearwardly from the interconnecting portion 114 in the vicinity of the juncture between the interconnecting portion 114 and the terminal portion 106 is a finger 120 that extends perpendicular to the interconnecting portion 114 and the terminal portion 106. The finger 120 includes a portion that extends outwardly of the terminal portion to engage a rib on the support 20 to aid in positioning the member 104 in either of the chambers A and B when the member 104 is secured on either of the terminal connecting portions 90 or 100.

When the electromagnet 16 of the switch 10 is deenergized, the movable contact carrier 18 is biased downwardly by the spring 66 to a position wherein the movable contact surfaces 64a and 64b engage the contact surfaces 70 and 74 and the contact surfaces 63:: and 63b are separated from the contact surfaces 68 and 72. Thus con act fing 64 y be considered as carrying the non mally closed contacts and the contact finger 63 the normally open contacts of the switch 10. Further, when the contact surfaces 64a and 64b engage the contact surfaces 70 and 74, the spring 65 will be compressed, and a circuit is completed between the terminal members 76 and 94, the finger 64 will be spaced from the lower wall 62, and the finger 63 will be pressed into engagement with the upper wall 60.

When the electromagnet 16 is energized, the contact carrier 18 will be moved upwardly against the force of the spring 66 to a position wherein the contact surfaces 63a and 63b are pressed against the contact surfaces 68 and 72 to complete a circuit between the terminal members 76 and 87. When the switch is in the energized condition, the spring 65 will be compressed, the finger 63 will be spaced from the upper wall 60, and the finger 64 will be in engagement with the lower Wall 62.

Conventional wire clamping arrangements, as are usually used with devices represented by the switch 10, usually include a conducting member which has a threaded opening wherein a screw is threaded to tighten a wire clamping member. This form of structure is illustrated by the wire connecting portion 80, the wire clamp 84, and the screw 82, which are provided to connect a bared end of a wire to the member 76. It will be seen that the terminal connecting portions 90 and 100 are provided with notches 92 and 102 which are not suited for use with conventional wire clamping arrangements so that the members 87 and 94 are not readily connectible through wires to an electric source. The member 104 is included in the switch 10 to permit either, but not both, of the members 87 and 94 to be connected to a current carrying conductor to thereby select the type of operations the switch 10 will perform in an electric circuit and permit the contacts to be visually inspected.

When the terminal connecting member 104 is connected to the terminal connecting portion 100', as illustrated by the arrangement in the chamber A in FIG. 1, the switch 10 will be programmed for a normally closed type of contact operation so that a load designated as 124 will be energized from a source of electric energy S when the switch 10 is de-energized and will be de-energized when the switch 10 is energized. The connection of the terminal connecting member 104 is accomplished by positioning the mounting portion 112 adjacent the rear face of the terminal connecting portion 100- with the threaded shank of the screw 108 positioned in the notch 102 and the head of the screw 108 positioned at the front face of the terminal connecting portion 100. When the screw 118 is tightened, the mounting portion 112 will be pressed against the rear face of the terminal connecting portion 100 and the head of the screw 118 will tightly engage the front face of the terminal connecting portion 100 to maintain the terminal connecting member 104 in its assembled position with the member 94. When the member 104 is assembled on the switch 10 in a manner illustrated by Chamber A, the member 94 may be readily connected in an electric circuit when a bared end of a wire conductor is secured to the terminal portion 106 by the screw 108 and the clamp 110. The interconnecting portion 114 of the member 104 is arranged to position the terminal portion 106 in spaced relation and forwardly of the terminal connecting portion 90 to prevent ready access thereto and thus preclude use of the normally open contacts in Chamber A of the switch 10.

When it is desired to convert the switch 10 from a normally closed contact operation to a normally open type of contact operation, the terminal connecting member 104 is detached from the portion 100 by loosening the screw 118 and detaching the member 104 so that it can be inverted and connected to the portion 90 as illustrated by the arrangement in the chamber B in FIG. 1. When the switch 10 is programmed for a normally open type of contact operation a load designated as 126 will be deenergized when the switch 10 is de-energized, and will be energized from the source S when the switch 10 is energized. The connection of the terminal connecting member 104 is accomplished by positioning the mounting portion 112 adjacent the rear face of the terminal connecting portion with the threaded shank of the screw 118 positioned in the notch 92 and the head of the screw 118 positioned at the front face of the terminal connecting portion 90. When the screw 118 is tightened, the mounting portion 112 will be pressed against the rear face of the terminal connecting portion 90 and the head of the screw 118 will tightly engage the front face of the terminal connecting portion 90 to maintain the terminal connecting member 104 in its assembled position with the member 94. Thus when the member 104 is assembled on f the switch 10 in a manner illustrated by chamber B, the

member 94 may be readily connected in an electric circuit when a bared end of a wire conductor is secured to the terminal portion 106 by the screw 108 and the clamp 110. The interconnecting portion 114 of the member 104 is arranged to position the terminal portion 106 in spaced relation and forwardly of the terminal connecting portion to prevent ready access thereto and thus preclude use of the normally open contacts in cham ber B of the switch 10.

While in the preferred embodiment of the present invention the switch 10 is provided with the terminal connecting member 104 which will permit the switch 10 to be programmed for either a normally open or a normally closed contact operation, as shown in FIG. 3, the members 87 and 94 may be provided with suitable openings in their terminal mounting portions designated as 90a and 100a which will receive conventional wire clamps and screws so the switch 10 may be wired to pro vide both normally open and normally closed contact operation. Further, while in the switch 10 as illustrated, the pair of fingers 63 and 64 and the spring 65 comprise the movable contact structure to bridge the contact surfaces 68 and 72, as well as the contact surfaces 70 and 74, if desired, the pair of fingers 63 and '64 may be replaced by a single finger which is resiliently positioned on the movable contact carrier 18 by a pair of springs in a manner which is readily apparent and well known to those skilled in the art to which this invention pertains.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto, a many variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation within the terms of the following claims.

What is claimed is:

1. In an electric switch, the combination comprising: a support, a contact actuator reciprocally movable along a linear axis between two axially spaced positions on the support, a first pair of stationary contacts positioned in the support in spaced relation to a first side of the actuator and having contact surfaces facing each other and spaced in a plane extending through the axis, a third stationary contact positioned in the support in spaced relation to a second side of the actuator that is opposite the first side, said third stationary contact and a first one of the pair of stationary contacts having contact surfaces facing in the same direction in a common plane that is normal to the axis, a fourth stationary contact positioned in the support in spaced relation to the second side of the actuator, said fourth and a second one of the pair of stationary contacts having contact surfaces facing in the same direction in a common plane that is normal to the axis and axially spaced from the plane common to the first and third stationary contacts, a movable contact structure resiliently mounted on the actuator, said movable contact structure including a first pair of electrically interconnected movable contact surfaces respectively spaced from the first and the second sides of the actuator and positioned by the actuator to be spaced from the first and the third stationary contacts when the actuator is at a first of the two positions and to engage the first and the third stationary contacts when the actuator is at a second of the two positions and a second pair of electrically interconnected movable contact surfaces respectively spaced from the first and the second sides of the actuator and positioned by the actuator to be spaced from the second and the fourth stationary contacts when the actuator is at the second position and to engage the second and the fourth stationary contact surfaces when the actuator is at the first position, a first member including a terminal connecting portion and a portion providing a support for the third stationary contact for connecting the third stationary contact to a first side of a first electric circuit, a second member including a terminal connecting portion spaced from the terminal connecting portion on the first member so that the terminal connecting portions on the first and the second members provide a pair of spaced portions and a portion providing a support for the fourth stationary contact for connecting the fourth stationary contact to a first side of a second electric circuit, a third member including a wire connecting terminal at one end and a portion extending from said end providing a common support for the first and the second stationary contacts and electrically interconnecting the first and the second stationary contacts for connecting the first and the second stationary contacts to a second side of the first and the second electric circuits, and a second terminal connecting member having a wire connecting portion spaced from and preventing access to a first one of the pair of spaced portions when the second terminal connecting member is secured to a second one of the pair of spaced portions.

2. The combination as recited in claim 1 wherein the switch is part of an electromechanically operated device and the first pair of stationary contacts are located between the axis and a rear wall of the support and the third and fourth stationary contacts are located between the axis and a front wall of the device.

3. The combination as recited in claim 2 wherein the movable contact structure includes a pair of spaced movable contact members having contact surfaces at the opposite ends thereof engageable with the contact surfaces on the first pair, the third and the fourth stationary contacts.

4. The combination as recited in claim 3 wherein the contact actuator has an opening therein and a spring positions the pair of movable contact members at opposite ends of the opening.

5. The combination as recited in claim 2 including a spring positioned between the actuator and the support for constantly urging the actuator toward one of the said two spaced positions.

6. The combination as recited in claim 1 wherein the terminal connecting portions of the first and the second members each include a notch and the second terminal connecting member includes a portion having a screw that is received in the notch for selectively securing the second terminal member to said first and second terminal connecting portions.

7. The combination as recited in claim 2 wherein the terminal connecting member on the third member is external of a top wall of the support and the terminal connecting portions of the first and the second members are external of a front wall of the support.

8. The combination as recited in claim 1 wherein the switch is a part of an electromechanically operated device, the actuator has an opening therein, the movable contacbstructure includes a pair of movable contact members each having contact surfaces at the opposite ends thereof engageable with the contact surfaces on the first pair, the third and the fourth stationary contacts and a spring positions the pair of movable contacts at the opposite ends of the opening, the first pair of stationary contacts are located between the axis and a rear wall of the support, the third and fourth stationary contacts are located between the axis and a front wall of the support, and a spring positioned between the actuator and the support constantly urges the actuator to one of the said two spaced positions.

9. The combination as recited in claim '8 wherein the terminal connecting portions of the first and the second members each include a notch and the second terminal connecting member includes a portion having a screw that .is received in the notch for selectively securing the second termlnal member to said first and second terminal connecting portions, the terminal connecting member on the third member is external of a top wall of the support and the terminal connecting portions of the first and the second members are external of a front wall of the support.

References Cited UNITED STATES PATENTS 2,585,824 2/1952 Noyes. 3,155,790 11/1964 Lemonnier 335-196 BERNARD A. GILHEANY, Primary Examiner H. BROOME, Assistant Examiner U.S. Cl. X.R. 200l66 

